Nitric oxide metabolite production in the human preimplantation embryo and successful blastocyst formation.

Eleven patients underwent controlled ovarian hyperstimulation yielding 72 embryos for evaluation. Mean nitric oxide metabolite levels in the insemination media were 2.6 times higher in embryos that progressed to blastocysts by culture day 5 than in those that did not. A comparison of the receiver operating characteristic curves between morphological predictors and nitric oxide metabolite levels revealed a trend toward a stronger association of insemination media nitric oxide metabolite with blastocyst formation.